You need a solution that keeps all this in mind whilst reducing costs and improving the amount collected.
Different demographics require different contact channels. Some people still prefer voice whilst other people never answer their phone and often pro-actively block calls from financial institutions. SMS is popular but has limitations in a collections environment, social media such as WhatsApp is popular whereas an organisations own Mobile App may be preferred by some.
The use of machine learning and ai chat bots is also a popular way of allowing customers to self serve. However what is clear is that no single channel is the solution for rapid contact and that the conversation needs to be continuous across orchestrated channels. If you send an SMS to a customer and they call in to your call centre, then your collections system and agents need to know that you sent an SMS and why.